False-colored SEM image of a migrating mouse dendritic cell (5.2 µm), showing membrane projections known as lamellipodia (green). Dendritic cells are sentinels of the immune system that are posted in peripheral tissues, ingest intruders and then migrate to the lymphoid organs. There, they expose some of their digested protein fragments (antigens) using their cell membrane as a showcase, report on the intruder and interact with- and instruct effector immune cells known as T-lymphocytes. Sophie Uzureau, Daniel Monteyne, Etienne pays and David Pérez-Morga, Université libre de Bruxelles.

Sleeping sickness is caused by a parasite: trypanosoma. In a new research published in Nature, the Molecular Parasitology lab (IBMM) publish a breakthrough discovery about the mecanism allowing some parasites to infect humans.
In 2003, En 2003, Pr Etienne Pays’ team already discovered that humans are naturally protected againts this type of pathogens owing to a serum protein called apolipoprotein L1 (apoL1), which efficiently kills the parasite by generating ionic pores in membranes of its digestive system. Through evolution, two variant trypanosomes acquired the ability to resist apoL1. These variant trypanosomes, named Trypanosoma rhodesiense and Trypanosoma gambiense, can therefore grow in human blood. It’s the mecanism which allows those parasite to resist to apoL-1 and infect humans that the researchers demonstrate today.

False-colored scanning electron microscopy image of innate immune cells and the parasite Trypanosoma brucei (purple; length: 15 micrometers) in an infected mouse liver. The parasite is transmitted between mammalian hosts, including humans, by the bite of infected tsetse flies and is responsible for human sleeping sickness, a lethal disease that is a serious problem in Africa. See page 463. Image: Gilles Vanwalleghem, Daniel Monteyne, Etienne Pays, and David Pérez-Morga, Laboratory of Molecular Parasitology and Center for Microscopy and Molecular Imaging, Université libre de Bruxelles, Gosselies, Belgium
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